The data point to a persistent perception gap among Americans. Despite strong evidence of crime dropping over recent decades, the public sees the reverse. "Recent Gallup polls have found that citizens overwhelmingly feel crime is going up even though it is not," says Professor Fox. "This is because of the growth of crime shows and the way that TV spotlights the emotional. One case of a random, horrific shooting shown repeatedly on TV has more visceral effect than all the statistics printed in a newspaper."
In many police departments across the US, changes during the past decade or more are hard to overstate, say many law enforcement experts.
Technology has given detectives powerful new tools with which to analyze blood and DNA samples or other forensic evidence, for instance.
Computerized "hot spot" crime mapping has also helped police connect dots in ways that were more difficult before.
From pushpins to databases
"We used to put pins on a map to figure out what the patterns were and where to concentrate our limited resources," says Tod Burke, a former police officer in Maryland who now teaches criminal justice at Radford University in Virginia. "Now we have databases and computers. It's really gotten a lot more sophisticated."